Technical Field
The present invention relates to a playback device for an aircraft to be mounted in an aircraft and which plays back at least either videos or sounds.
Related Art
Playback devices for playing back videos and sounds are mounted in an aircraft in order to improve services for passengers and transmit security information to the passengers. Since the aircraft frequently undergoes large vibrations in the middle of a flight or during takeoff, a playback device for an aircraft is required to have high vibration resistance. Moreover, since the aircraft stays on standby at an airport in a thermal area, the aircraft playback device is also required to have heat resistance.
For these reasons, a plurality of cooling techniques have already been proposed to dissipate heat quickly from a heat source (e.g., a circuit board, a power unit, and others) incorporated in the playback device and efficiently inhibit an increase in temperature of the playback device.
However, in an existing cooling mechanism, a cooling fan is often placed in close proximity to or in contact with a periphery of a casing. Moreover, in the existing cooling mechanism, an inlet for taking in air and an outlet for releasing air are provided on respective sides of a rotating shaft of a fan. The heat source is interposed between the inlet and the outlet. Thus, the existing cooling mechanism that lets air out in substantially a straight manner poses many limitations on a layout relationship between the cooling fan and the heat source, thereby providing a low degree of design freedom.
Such limitations on the layout of the cooling fan and the heat source pose a great problem on the aircraft playback device that includes many members whose positions cannot be changed in view of a design, such as dampers for vibration control and setscrews for fixing the playback device in the cabin.
JP H11-112177 A describes a technique of causing air used for forcedly cooling a first heating member (a transistor) by air to collide with a guide plate positioned behind a cooling fan, thereby diverting a direction of the air; letting the air out from an outlet formed in a case; and promoting natural-air-cooling of a second heating member (an IC) placed behind the guide plate by utilization of a negative pressure developing around the outlet. According to the technique, the direction of an exhaust stream is changed by the guide plate, so that a degree of design freedom can be improved to some degree.
However, according to the technique stated in JP H11-112177 A, the first heating member is forcedly cooled by air by utilization of an intake stream that occurs as a result of air, which flows into an inlet formed in the casing, being drawn by the cooling fan. In order to enhance a cooling effect of the intake stream as mentioned above, the quantity of air flowing in through the inlet must be maximized. To this end, a rotation axis of the cooling fan and the inlet must be aligned in a row. Namely, a sufficient improvement in degree of design freedom cannot be attained by the technique, described in JP H11-112177 A, of cooling the first heating member by the intake stream. According to JP H11-112177 A, the inlet and the outlet are formed only in one position. Hence, the quantity of inflow and outflow air is small. Further, fins of the heat sink extend in a vertical direction with respect to an air stream occurring above the heat sink. Since the air stream is hindered by the fins and becomes likely to build up, cooling efficiency cannot be said to be high.
Accordingly, the present invention provides a playback device for an aircraft that holds a high level of cooling efficiency and achieves a higher degree of design freedom.